Over the last few months, the Obama-Biden campaign and its allies have offered up phony issues to drive the national political conversation — the Buffett rule, the “war on women,” the student-loan fight, the “Life of Julia” ad, the gay-marriage debate and so on. From the president to the lowliest MSNBC Democratic talking heads, the party has focused on one silly item after another.

Usually, these diversions are saved for the fall, when voters start to pay attention. Why are they so intent on dominating the news with manufactured pseudo issues so early in the presidential campaign?

Yes, part of it is about distracting voters from the weak economy, persistently high unemployment, ballooning deficits and so on and the administration’s failure to deal with those. But there’s more to the story.

Remember: When he first emerged nationally, Barack Obama promised to move the country past its petty divisions and to focus on the big challenges that face all of us together. This was the central theme of his lauded “Red State/Blue State” address at the 2004 Democratic convention, as well as of his second autobiography, “The Audacity of Hope.” A big reason for his failure to do so as president has to do with the way his party is organized.

Over the last 80 years, the Democrats have added scores of “client groups” — organized interests that are loyal to its banner partly for the special benefits they receive from the party.

Franklin Roosevelt was the first to bring this ethos — which had been prominent in 19th-century urban machines like New York’s very own Tammany Hall — to Washington.

Earlier leaders had rewarded their loyalists with jobs and contracts, but FDR used the new powers of big, expansive government to curry favor with whole classes of citizens: Organized labor won powers through the National Labor Relations Act; plantation owners in the segregationist South got huge agricultural subsidies; big-city bosses bathed in an unprecedented stream of federal patronage via the Works Progress Administration.

FDR’ssuccessors tried — sometimes successfully— to add clients, all in the hope of building a permanent Democratic majority. But by the end of the 1960s — with the addition of environmentalists, public-sector labor, feminists and so on — there were just too many of them.

FDR managed to keep all his groups happy while advancing the public good (as he saw it), but every Democratic president since Jimmy Carter has failed in this balancing act. The party has become like a juggler who adds too many balls to his routine only to see them all come crashing down.

Obama falls into this category — and then some. Carter and Bill Clinton tried, with varying degrees of success, to balance the public interest and the managing of Democratic clients. Obama hasn’t.

From the start, Obama ceded control of policymaking to congressional Democrats — who are the most susceptible to party clients’ demands. The stimulus, ObamaCare, financial reform, the auto bailout — all were crafted with the interests of key Democratic clients in mind, at the expense of the public good.

ObamaCare is a great case in point: Unions, feminists and big businesses all won huge payoffs thanks to the bill, while the average American will see his premiums rise and his insurance become less secure.

So is it really a surprise that Obama would run for re-election by trying to pick apart the US public, promising special favors to this or that group? After all, that’s precisely how he’s governed. Plus, given that he hails originally from Chicago — a shrine to modern Democratic patronage — it’s likely how he thinks politics should operate.

But it isn’t. Our Founding Fathers bequeathed to us a republican system of government, which was to be responsive to the public interest, not the demands of a privileged few. In the 1820s, Andrew Jackson — the first true people’s president — founded a party to restore the old republican virtues. Today, we call that the Democratic Party — but it’s come to represent so much of what Jackson opposed.

Obama’s shameless re-election campaign, promising special goodies to one group after another, is an especially tragic commentary on what has gone wrong with the world’s oldest political party.

Jay Cost is a staff writer for The Weekly Standard. His new book is “Spoiled Rotten: How the Politics of Patronage Corrupted the Once Noble Democratic Party and Now Threatens the American Republic.”